Interaction of α-Gliadin with Poly(HEMA-co-SS): Structural Characterization and Biological Implication

The wheat gluten protein alpha-gliadin, a well known trigger of celiac disease, can be complexed by random copolymers of hydroxyethyl methacrylate (HEMA) and sodium 4-styrene sulfonate re (SS). In this work, influence of alpha-gliadin and poly(HEMA-co-SS) concentrations on alpha-gliadin structure was studied using spectroscopic techniques and dynamic light scattering, In 70916 ethanol or 0.06M HCI (pH 1.2), alpha-gliadin was found to self-associate upon increasing its concentrations and displayed decreased alpha-helical content and increased P-turn and P-sheet contents. At pH 1.2, alpha-gliadin interacted with poly(HEMA-co-SS) to form supra-molecular complex particles. Poly(HEMA-co-SS) induced alpha-gliadin structural changes that mimicked those obtained by varying the protein concentration in pure solution. At pH 6.8, alpha-gliadin was poorly soluble and formed large particles but alpha-helix is still main secondary structure. The influence of the polymer on protein structure was weaker at neutral than acidic pH. Interaction with poly(HEMA-co-SS) disrupted alpha-gliadin conformation and self-association to form new complex particles at neutral pH. This study provides insight into the mechanism of poly(HEMA-co-SS)alpha-gliadin interaction and the polymer as a-gliadin sequestering agents in the supportive treatment of celiac disease. (c) 2008 Wiley Periodicals, Inc. Biopolymers 91: 169-178 2009.